April 8, 1920] 



NATURE 



73 



feel certain that no one who has had experience 

 in work of this character will for a moment ques- 

 tion whether this percentage of food, which is con- 

 ferring a benefit upon agriculture, balances the 

 injury that is inflicted upon an inexhaustible and 

 ever-increasing fish supply. 



Very similar figures might be advanced for the 

 remaining species, none of which are taking more 

 than 20 per cent, of hsh per annum of their total 

 bulk of food. Is the sea so impoverished that we 

 cannot afford these birds this amount of fish-food 

 in exchange for their beneficial action in destroying 

 more than 20 per cent, of injurious insects (of 

 which 7'2 per cent, consist of wireworms in the 

 case of the black-headed gull)? 



Fig. I. — Diagrammatic repre^entaiicn of the percentage of food of the 

 black-headed gull. The portions shaded by longitudinal lines represent 

 food that it is beneficial the birds should eat ; those stippled, food that 

 it is injurious they should eat, and the blank portions food of a neutral 

 nature. 



The records, both individually and collectively, 

 show that the bulk of the food of these birds is 

 not fish, but animal matter of a neutral nature. 

 Of course, if one classes all annelids, non-edible 

 Crustacea, and molluscs as fish food, then very 

 difi"erent figures may be obtained ; but those who 

 are acquainted with the abundance and the nature ; 

 of the marine life cast up on the shore will agree I 

 with us in regarding these as a neutral factor. ! 



If the figures are summarised for all the species ; 

 in class (iii) (so far as our investigation has gone), ' 



I the verdict is certainly in favour of these birds. 



! It is very easy to condemn a species because at 



j some particular season of the year or in some 



district a certain number have been found to be 



j feeding upon food fishes; but, as has been fre- 



I quently pointed out, such partial records do not 



I give a true estimate of the food as a whole. It 



! must not for one moment be thought that we are 



I endeavouring to explain away the injuries inflicted, 



I but we contend that it is unfair to judge any 



species of wild bird upon a local or partial record ; 



the nature of the food generally throughout the 



United Kingdom and over the whole year is what 



j we have endeavoured to learn. 



Very interesting results have been obtained as to 

 the seasonal changes of food and the variations 

 in different localities. Sex and age also influence 

 the quantity of food taken, and although the 

 figures are yet incomplete, they point to the fact 

 that the males take a larger quantity of food than 

 the females, and the young birds more than 

 the old. 



It is not within the province of this inquiry to 

 discuss the question of the impoverishment of the 

 sea, but it will be impossible to conclude it without 

 taking cognisance of the leading views on the 

 subject and their bearing upon this question. 



Finally, all the work goes to show that with a few 

 exceptions — e.g. the cormorant and the shag — 

 the food of each species is partly beneficial, and, 

 even if for the moment we admit that the per- 

 centage of the fish destroyed is an injury, we 

 must take into consideration the benefits derived 

 by reason of the nature of the remaining food. 

 This varies in different seasons of the year and 

 according to the nature of the locality, but if an 

 average is taken of the eleven species in 

 class (iii), we find that the total percentage of 

 injuries is less than that of the benefits, and that 

 the bulk of the food is of a neutral nature. 



It is obvious that, after examining upwards of 

 three thousand specimens, with the results 

 obtained, the question of the food of our com- 

 moner sea-birds and their effect upon the fisheries 

 and agriculture can no longer remain where it 

 was ; and, whilst not advocating any special pro- 

 tection, except in one or two cases, any agitation 

 for their destruction cannot be condemned too 

 forcibly, for, altogether apart from sentimental 

 reasons, it is extremely unlikely that our fisheries 

 would benefit or show any marked improvement, 

 even were hundreds of thousands of these birds 

 destroyed annually, whilst agriculture would 

 certainly be the sufferer by such a loss. 



The Imperial College of 



'T'HE Chancellor of the Exchequer, speaking in 

 -*■ the House of Commons on March 16, \ 

 expressed concern at the extraordinary expansion j 

 of business in the promotion of companies, and 

 said he was convinced that the time had come j 

 when part of the money thus called for only 

 creates increased competition for the limited 

 NO. 2632, VOL. 105] 



Science and Technology. 



supplies of labour and material which are all that 

 are available. Few of us can doubt that this 

 concern of the Chancellor is more than justified, 

 but it is not only for purely industrial enterprise 

 that appeals to the public at large are being made 

 daily for large sums of money. Owing to the 

 universal rise in prices, educational institutions 



